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Rajkumar S

2006-Nov-13 08:17 UTC

using find to get the value from a table referenced by foreign key

Hello all,

I have 2 tables calls and clients:

clients:
+-----------+---------+------+-----+---------+----------------+
| Field     | Type    | Null | Key | Default | Extra          |
+-----------+---------+------+-----+---------+----------------+
| id        | int(11) |      | PRI | NULL    | auto_increment |
| ivr_id    | int(11) | YES  | MUL | NULL    |                |
| is_online | char(1) | YES  |     | NULL    |                |
+-----------+---------+------+-----+---------+----------------+

calls:
+-------------+--------------+------+-----+---------+----------------+
| Field       | Type         | Null | Key | Default | Extra          |
+-------------+--------------+------+-----+---------+----------------+
| id          | int(11)      |      | PRI | NULL    | auto_increment |
| src         | varchar(80)  | YES  |     | NULL    |                |
| start       | datetime     | YES  |     | NULL    |                |
| ivr_id      | int(11)      | YES  | MUL | NULL    |                |
| file_name   | varchar(255) | YES  |     | NULL    |                |
+-------------+--------------+------+-----+---------+----------------+

Here calls.ivr_id is the foreign key referring to clients.ivr_id

Corresponding models are :

class Call < ActiveRecord::Base
  belongs_to :client, :foreign_key => "ivr_id"
  def self.calls_and_is_online (from_time, to_time)
    find (:first,
          :conditions => [
            "start > :from_time and start <= :to_time
             and ivr_id <> 0
             and file_name like ''%wav''",
            {:from_time => from_time, :to_time => to_time}
          ])
  end
end

class Client < ActiveRecord::Base
  has_one :call, :foreign_key => "ivr_id"
end

My call_controller has a method

  def get_calls_and_is_online
    @date = Time.parse(params[:date])
    @calls_and_is_online = Call.calls_and_is_online(@date, @date+1.day)
  end

From my controller I can get all the details of call table with out
any problems. Now I want to get the is_online status of a call. The
rails book Chap: 18 says I can define some thing like price
line_item.product.price, but in my case when I use
<%@calls_and_is_online.client.is_online %> from my view, I get the error

 NoMethodError in Call#get_calls_and_is_online

I know that I am missing some thing small, but not able to find what,
even after searching a lot... Any helping hand here is much
appreciated.

raj

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Rajkumar S

2006-Nov-13 11:18 UTC

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Re: using find to get the value from a table referenced by foreign key

Hi,

Following up more on this...

On 11/13/06, Rajkumar S
<rajkumars-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
wrote:> Hello all,
>
> I have 2 tables calls and clients:
>
> clients:
> +-----------+---------+------+-----+---------+----------------+
> | Field     | Type    | Null | Key | Default | Extra          |
> +-----------+---------+------+-----+---------+----------------+
> | id        | int(11) |      | PRI | NULL    | auto_increment |
> | ivr_id    | int(11) | YES  | MUL | NULL    |                |
> | is_online | char(1) | YES  |     | NULL    |                |
> +-----------+---------+------+-----+---------+----------------+
>
> calls:
> +-------------+--------------+------+-----+---------+----------------+
> | Field       | Type         | Null | Key | Default | Extra          |
> +-------------+--------------+------+-----+---------+----------------+
> | id          | int(11)      |      | PRI | NULL    | auto_increment |
> | src         | varchar(80)  | YES  |     | NULL    |                |
> | start       | datetime     | YES  |     | NULL    |                |
> | ivr_id      | int(11)      | YES  | MUL | NULL    |                |
> | file_name   | varchar(255) | YES  |     | NULL    |                |
> +-------------+--------------+------+-----+---------+----------------+
>
> Here calls.ivr_id is the foreign key referring to clients.ivr_id
>
> Corresponding models are :
>
> class Call < ActiveRecord::Base
>   belongs_to :client, :foreign_key => "ivr_id"
>   def self.calls_and_is_online (from_time, to_time)
>     find (:first,
>           :conditions => [
>             "start > :from_time and start <= :to_time
>              and ivr_id <> 0
>              and file_name like ''%wav''",
>             {:from_time => from_time, :to_time => to_time}
>           ])
>   end
> end
>
> class Client < ActiveRecord::Base
>   has_one :call, :foreign_key => "ivr_id"
> end
>
> My call_controller has a method
>
>   def get_calls_and_is_online
>     @date = Time.parse(params[:date])
>     @calls_and_is_online = Call.calls_and_is_online(@date, @date+1.day)
>   end
>
> From my controller I can get all the details of call table with out
> any problems. Now I want to get the is_online status of a call. The
> rails book Chap: 18 says I can define some thing like price >
line_item.product.price, but in my case when I use <%>
@calls_and_is_online.client.is_online %> from my view, I get the error
>
>  NoMethodError in Call#get_calls_and_is_online
I added the following in my view:

<%= xx = Call.find (56755) %>
<%= debug(xx.client.class) %>

<%= yy = Client.find(41842) %>
<%= debug (yy.call.class) %>

The corresponding sql queries are:
  Call Columns (0.000880)   SHOW FIELDS FROM calls
  Call Load (0.000436)   SELECT * FROM calls WHERE (calls.id = 56755) LIMIT 1
  Client Load (0.000318)   SELECT * FROM clients WHERE (clients.id 17575) LIMIT
1
  Client Load (0.000303)   SELECT * FROM clients WHERE (clients.id 41842) LIMIT
1
  Client Columns (0.000466)   SHOW FIELDS FROM clients
  Call Load (0.052974)   SELECT * FROM calls WHERE (calls.ivr_id = 41842)

The corresponding values in datbase are:

SELECT ivr_id FROM calls WHERE (calls.id = 56755) LIMIT 1
+--------+
| ivr_id |
+--------+
|  17575 |
+--------+

In the second query, you can see that the value of 17575, is fine, but
it should have queried for clients.ivr_id instead of clients.id.

Now to the third query:

SELECT ivr_id FROM clients WHERE (clients.id = 41842) LIMIT 1;
+--------+
| ivr_id |
+--------+
|  14302 |
+--------+

but the fourth query is SELECT * FROM calls WHERE (calls.ivr_id = 41842)

Here the inverse of the previous problem happened, calls.ivr_id is
correct, but the value is 41842, while it should have been 14302.

I get a feeling that I have messed up the belongs_to and has_many but
I am not able to figure out what it is :(

raj

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Alan C Francis

2006-Nov-13 15:08 UTC

head link

Re: using find to get the value from a table referenced by f

Hi Rajkumar,

Is there reason you can''t just have a client_id field in the Call and
let Rails to the work ?

I''m assuming the ivr_id field is some kind of "3rd party"
information
and it might be better to not use that as the FK relationship between
client and call.

A.

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Rajkumar S

2006-Nov-14 10:41 UTC

head link

[Fixed] Re: using find to get the value from a table referenced by foreign key

I have finally fixed this:

I was over riding the rails configuration at two places.

1. Primary key in Clients table is ivr_id instead of id
2. Foreign key referreng to clients table is ivr_id instead of client_id

So this involves letting rails know that I have overridden the
conventions at 2 places,

1. in Clients.rb use set_primary_key "ivr_id" so that rails know that
the primary key is ivr_id instead of id
2. in Calls.rb use belongs_to :client, :foreign_key => "ivr_id" so
that rails know that it should use ivr_id instead of client_id

The actuall files are

class Call < ActiveRecord::Base
  belongs_to :client, :foreign_key => "ivr_id"

class Client < ActiveRecord::Base
  set_primary_key "ivr_id"
  has_many :calls

Thanks every one,

raj

On 11/13/06, Rajkumar S
<rajkumars-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
wrote:> Hi,
>
> Following up more on this...
>
> On 11/13/06, Rajkumar S
<rajkumars-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
> > Hello all,
> >
> > I have 2 tables calls and clients:
> >
> > clients:
> > +-----------+---------+------+-----+---------+----------------+
> > | Field     | Type    | Null | Key | Default | Extra          |
> > +-----------+---------+------+-----+---------+----------------+
> > | id        | int(11) |      | PRI | NULL    | auto_increment |
> > | ivr_id    | int(11) | YES  | MUL | NULL    |                |
> > | is_online | char(1) | YES  |     | NULL    |                |
> > +-----------+---------+------+-----+---------+----------------+
> >
> > calls:
> > +-------------+--------------+------+-----+---------+----------------+
> > | Field       | Type         | Null | Key | Default | Extra          |
> > +-------------+--------------+------+-----+---------+----------------+
> > | id          | int(11)      |      | PRI | NULL    | auto_increment |
> > | src         | varchar(80)  | YES  |     | NULL    |                |
> > | start       | datetime     | YES  |     | NULL    |                |
> > | ivr_id      | int(11)      | YES  | MUL | NULL    |                |
> > | file_name   | varchar(255) | YES  |     | NULL    |                |
> > +-------------+--------------+------+-----+---------+----------------+
> >
> > Here calls.ivr_id is the foreign key referring to clients.ivr_id
> >
> > Corresponding models are :
> >
> > class Call < ActiveRecord::Base
> >   belongs_to :client, :foreign_key => "ivr_id"
> >   def self.calls_and_is_online (from_time, to_time)
> >     find (:first,
> >           :conditions => [
> >             "start > :from_time and start <= :to_time
> >              and ivr_id <> 0
> >              and file_name like ''%wav''",
> >             {:from_time => from_time, :to_time => to_time}
> >           ])
> >   end
> > end
> >
> > class Client < ActiveRecord::Base
> >   has_one :call, :foreign_key => "ivr_id"
> > end
> >
> > My call_controller has a method
> >
> >   def get_calls_and_is_online
> >     @date = Time.parse(params[:date])
> >     @calls_and_is_online = Call.calls_and_is_online(@date,
@date+1.day)
> >   end
> >
> > From my controller I can get all the details of call table with out
> > any problems. Now I want to get the is_online status of a call. The
> > rails book Chap: 18 says I can define some thing like price > >
line_item.product.price, but in my case when I use <%> >
@calls_and_is_online.client.is_online %> from my view, I get the error
> >
> >  NoMethodError in Call#get_calls_and_is_online
>
> I added the following in my view:
>
> <%= xx = Call.find (56755) %>
> <%= debug(xx.client.class) %>
>
> <%= yy = Client.find(41842) %>
> <%= debug (yy.call.class) %>
>
> The corresponding sql queries are:
>   Call Columns (0.000880)   SHOW FIELDS FROM calls
>   Call Load (0.000436)   SELECT * FROM calls WHERE (calls.id = 56755) LIMIT
1
>   Client Load (0.000318)   SELECT * FROM clients WHERE (clients.id >
17575) LIMIT 1
>   Client Load (0.000303)   SELECT * FROM clients WHERE (clients.id >
41842) LIMIT 1
>   Client Columns (0.000466)   SHOW FIELDS FROM clients
>   Call Load (0.052974)   SELECT * FROM calls WHERE (calls.ivr_id = 41842)
>
> The corresponding values in datbase are:
>
> SELECT ivr_id FROM calls WHERE (calls.id = 56755) LIMIT 1
> +--------+
> | ivr_id |
> +--------+
> |  17575 |
> +--------+
>
> In the second query, you can see that the value of 17575, is fine, but
> it should have queried for clients.ivr_id instead of clients.id.
>
> Now to the third query:
>
> SELECT ivr_id FROM clients WHERE (clients.id = 41842) LIMIT 1;
> +--------+
> | ivr_id |
> +--------+
> |  14302 |
> +--------+
>
> but the fourth query is SELECT * FROM calls WHERE (calls.ivr_id = 41842)
>
> Here the inverse of the previous problem happened, calls.ivr_id is
> correct, but the value is 41842, while it should have been 14302.
>
> I get a feeling that I have messed up the belongs_to and has_many but
> I am not able to figure out what it is :(
>
> raj
>
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Rails - Nov 2006 - using find to get the value from a table referenced by foreign key

using find to get the value from a table referenced by foreign key

Re: using find to get the value from a table referenced by foreign key

Re: using find to get the value from a table referenced by f

[Fixed] Re: using find to get the value from a table referenced by foreign key